Thiophosphoric acid esters and their production



United States Patent TH IOPH OSPHORIC ACID ESTERS AND THEIR PRODUCTIONGerhard S chrader, Opladen, Germany, assignor to Farbenfabrlken Bayer.Aktiengesellschaft, LeverkusemGermany, a corporation of Germany NoDrawing. Application September 5,1956

Serial No. 607,989

Claims priority, application Germany September 7, 1955 12 Claims. (Cl.260-461 This invention relates to, and has as its objects new and usefulthiophosphoric acid esters and their preparation. Generally these newesters correspond to the formula r In this formula R stands for an alkyl(especially lower alkyl) or aryl (especially phenyl) radical, A is alower alkylene radical, especially an ethylene chain and R stands for acarboxylic acid ester radical, an amino-alkyl radical, a free oresterified hydroxyalkylmercapto-radical or an alkylmercapto,arylmercapto, alkoxyor aryloxy radical.

Many thiophosphoric acid esters have become very important pesticides orplant protecting agents recently. It has now been found that effectivecompounds of this class of phosphor insecticides may be obtained by.reacting 0.0-diesters of thiophosphoric acid halides with alcohols ofthe general formula in which A and R stand for the above mentionedradicals. Typically this reaction may be shown by the followingequation: (I) i s on1," H C:OOC--CH2.S-CH:'-CHa-OH Ci -P Instead of thediethylester of thiophosphoric acid chloride also other esters such asthe dimethyl, diprop'yl, dibutyl, diphenyl, dicyclohexyl, etc., estermay be used. Mixed esters of these types may also be used. Instead ofthe acid-chloride also other acid halides such as the bromide areconvenient.

As to the second reactant in this equation which 'corresponds to theformula and for which in the above typical equation the radical R isshown as a carboxylic ester radical, also various other compounds may beused. Thus, the radical R may be any other carboxylic acid ester such asthe other lower alkyl (e.g. methyl-, propyl-, butyl-, amy1-,) phenylorcycloalkyl (e.g. cyclohexyl or cyclopentyl) esters. R further may be analkyl amino radical of the formula Patented Oct. 20, 1959 2 wherein X isa lower alkylene, such as a methylen ethylene, propylene, butylene-,etc. and R and R stand for lower alkyl radicals such as methyl-, ethyl-,propyl-, butyl-, etc. radicals, oi

may form a ring such as piperidine, piperazine, morpholine or the like.R also may be the residue of a hydroxyalkyl mercaptan or its esters ofthe formula SY-OR wherein Y stands for lower alkylene and R stands forhydrogen or the radical of an organic or inorganic acid, thus forming anester of the hydroxy alkyl mercaptan. At last R may also be representedby the formula -SCH -ZR wherein R stands for alkyl or aryl radicals suchas the methyl-, ethyl-, propyl-, butyl-, amy1, hexyl-, phenylgroup, etc.and Z stands for oxygen or sulfur.

The alcohols can be prepared by processes known by the art, for exampleby reacting a hydroxy alkyl mercaptan with a compound of the formula R--CH hal, wherein R has the above defined meaning and wherein hal standsfor a halogen like chlorine, at slightly elevated temperature andpreferably in the presence of an acid-binding agent and an inertdiluent.

The reaction shown in the above Equation I, generally is carried out byheating the alcoholates such as the sodium or potassium alcoholates ofthe above alcohols with thethiophosphoric acid halides or by mixing thefree alcohols and acid halides and splitting off hydrohalogenacid byacid-binding agents such as sodium methylate, sodium ethylate, sodiumcarbonate, potassium carbonate, pyridine, quinoline, etc. Sometimes theuse of metallic catalysts such as copper powder may be advantageous. Thereaction furthermore should preferably be carried out in inert solventssuch as liquid alcohols, ketones, hydrocarbons, etc.; especiallysuitable are e.g. methanol, ethanol, methyl-ethyl-ketone, benzene,toluene, xylene, etc. The reaction temperature may vary within widelimits. Temperatures from 0 to about 250 C. may be used, especiallysuitable are temperatures from about 30 to about C.

The compounds of the present invention are generally valuableinsecticides and plant-protecting agents. They kill pests such asaphids,'flies and mites and exhibit a very remarkable systemic action.The application of these compounds should be carried out according tothe use of other known phosphor insecticides, i.e. in dilution orsolution with solid or liquid carriers such as chalk, talc, bentonite,water, alcohols, liquid hydrocarbons, etc. The inventive compounds mayfurther be used in combination with other known insecticides orpesticides, etc. Efiective concentrations of the compounds may varyalso; generally concentrations of 0.0001% to 1.0% kill pestseffectively. The combination of the compounds may be sprayed or dustedor otherwise brought in contact with pests or plants to be protected.They may also be used as aerosols.

The following examples are given by way of illustration only Withoutlimiting the present invention thereto.

50 grams of ethyl-(fl-hydroxyethyl-thio-glycolate) are dissolved in 200cc. of toluene. 45 grams of potassium carbonate and 1 gram of copperpowder are added. At 85-90 C. there are added dropwise 60 grams of 0,0-diethyl-thiophosphoric acid chloride. The mixture is then kept at 90 C.for further three hours. After cooling and filtering off fromprecipitated salts the solvent is distilled off. There are obtained 60grams of the new ester boiling at 170 C. at 2 mm. Hg.

This ester kills flies in a concentration of 0.01% completely andfurthermore exhibits systemic action.

The ethyl-(,B-hydroxyethyl-thio-glycolate) can be obtained as follows:

40 grams of the hydroxy-ethyl mercaptan are dissolved in 300 cc. ofmethyl-ethylketone. Upon adding 75 grams of finely divided potassiumcarbonate, 62 grams of chloroacetic acid ethyl ester are added dropwiseat 40 C. The reaction mixture is kept for one hour at the sametemperature. After cooling and filtering off from precipitated salts thereaction mixture is fractionated. There are obtained 57 grams ofethyl-(B-hydroxyethyl-thio-glycolate) boiling at 108 C. at 2 mm. Hg.

65 grams of 8-hydroxyethyl-)-(ethoxymethyl-) mercaptan are dissolved in300 cc. of toluene. 75 grams of potassium carbonate and 3 grams offinely divided copper are added. While stirring there are added dropwise95 grams of 0,0-diethyl-thiophosphoric acid chloride at 8090 C. Thistemperature is maintained for about further 4 hours. The followingprocedure is carried out according to the description of Example 1.Thereare obtained 40 grams of the new ester of the above formula,boiling at 2 mm. Hg at 138 C. This ester kills aphids within aconcentration of 0.01% completely and shows systemic properties.

The (fl-hydroxyethyl)-(ethoxymethyl-) mercaptan can be obtained asfollows:

40 grams of hydroxyethyl-mercaptan are dissolved in 300 cc. ofmethyl-ethylketone. Upon adding 75 grams of finely divided potassiumcarbonate while stirring, 50 grams of ot-chloromethylcthyl ether areadded dropwise ata temperature of 40 C. The reaction mixture is kept atthe same temperature for about one hour. After cooling and filtering offfrom precipitated salts, the reaction mixture is fractionated. There areobtained 35 grams of (fl-hydroxyethyL)-(ethoxymethyl-) mercaptan boilingat 71 C. at 2 mm. Hg.

Example 3 CH2'OOH3 001115 61 grams of (fl-hydroxyethyh)-(methoxymethyl-)mercaptan are dissolved in 250 cc. of toluene and there are added 75grams of potassium carbonate and 2 grams of copper powder. 95 grams of0,0-diethyl-tl1iophosphoric acid chloride are then added dropwise at 85C. This temperature has to be maintained for further 3 hours. Thefollowing procedure is to be seen from Example 1. There are obtained 41grams of the above ester boiling at 2 mm. Hg at 132 C.

The (B-hydroxethyb)-.(methoxymethyl-) mercaptan is obtained as follows:

40 grams of hydroxyethyl-mercaptan are dissolved in 300 cc. ofmethyl-ethylketone. Upon adding 75 grams of finely divided potassiumcarbonate, 42 grams of fl-chloromethyl-methyl ether are added at atemperature of 40 C. while stirring. The reaction mixture is kept at thesame temperature for about one hour. After cooling and filtered off fromprecipitated salts, the reaction mixture is fractionated. There areobtained 32 grams of (5- 4 hydroxyethyl-)-(methoxymethyl-) mercaptanboiling at 62 C. at 2 mm. Hg.

Example 4 V s 0cm,

54 grams of (fi-hydroxyethyL) (B-[dicthylamino-J ethyl-) mercaptan aredissolved in 200 cc. of toluene. 45 grams of potassium carbonateand 2grams of finely divided copper are added. At a temperature of about C.there are added dropwise 58.5 grams of 0,0- diethyl-thiophosphoric acidchloride and this temperature is kept for about two more hours. Thefollowing procedure is to be seen from Example 1. There are obtained 50grams of the'newester as a colorlessand-water insoluble oil whichdistils'underdecomposition even in high-vacuum distillation.

The fi-hydroxyethyL) (B diethylamino-l ethyl-) mercaptan is obtained asfollows:

'40 grams of hydroxyethyl mercaptan are dissolved in 300 cc. ofmethyl-ethylketone. Upon adding 75 grams of finely divided potassiumcarbonate, 68 grams of 2- diethylamino-Z-chloroethane are added dropwiseat a temperature of 40 C. The reaction mixture is kept for one hour atthe same temperature. After cooling and filtering off from precipitatedsalts the reaction mixture is fractionated. There are obtained 74 gramsof ({3- hydroxyethyl-)-(;8-[diethylamino-1ethyl) boiling at 104 C. at2mm. Hg.

Example 5 v Hz-o 0 1171 0 07115 23 grams of(B-hydroxyethyL)-(isopropylhydroxymethyl'-) mercaptan are mixed with 15grams of pyridine. At 40 C. there are added 29 grams of 0,0-diethylthiophopshoric acid chloride. The mixture has to be cooled so that thereaction temperature does not rise over 40 C. After stirringthe mixturefor one further hour, itis poured in ice 'water (300 cc.) containing 20ml. of concentrated hydrochloric acid. The precipitated oil is taken upin 200 cc. of chloroform. The chloroform solution is washed twice with20 cc. of water and then dried over sodium sulfate. After distilling offthe solvent there are-obtained 43 grams of the new ester, distilling at0.01 mm. Hg at C.

The (13 hydroxyethyl (isopropylhydroxymethyl-) mercaptan is obtained asfollows:

40 grams of hydroxyethylmercaptan are dissolved in 300 cc. ofmethyl-ethylketone. Upon adding 75 grams of finely divided potassiumcarbonate, 55 grams of achloromethyl-isopropyl other are added dropwiseat a temperature of 40 C. The same temperature is kept for another hour.After cooling and filtering off from precipitated salts the reactionmixture is fractionated. There are obtained 35 grams of(fl-hydroxyethyl-)-(isopropylhydroxymethyl-) mercaptan boiling at 89 C.at 2 mm. Hg.

Example 6 OH r-O O S 02H S \CHZCHZO-P 53 grams of (B-hydroxyethyL)-(sec.butyl-hydroxymethyl-) mercaptan are dissolved in 35 grams of pyridine.51 grams of 0,0-diethyl-thiophosphoric acid chloride are added at 40 C.not allowing the temperature 0 CiH;

cc. of water containing 20 cc. of hydrochloric acid (cone). The furtherrecovering of the new ester is carried out in accordance with thedescription in Example 5. There are obtained 70 grams boiling at 0.01mm. Hg at 120 C. This ester kills aphids in a concentration of 0.01%vcompletely and has systemic properties.

The (B hydroxyethyl )-(sec.-butyl-hydroxymethyl-) mercaptan is obtainedas follows:

40 grams of hydroxyethyl mercaptan are dissolved in 300 cc. ofmethyl-ethylketone. Upon adding 75 grams of finely divided potassiumcarbonate, 62 grams of cachloromethyl-sec.-butyl ether are addeddropwise at 40 C. The reaction mixture is thereafter kept for another 15minutes at the same temperature. After cooling and filtering off fromprecepitated salts the reaction mixture is fractionated. There areobtained 53 grams of (B- hydroxyethyl-)-(sec.-butyl hydroxymethyh)mercaptan boiling at 58 C. at 0.01 mm. Hg.

- action against moths and white ants.

The di-(p-hydroxyethyl-) mercaptan can be obtained as follows:

20 grams of hydroxymethyl mercaptan are dissolved in 50 cc. of methanol.Upon adding an alcoholic sodium methylate solution containing 2/10 molof sodium methylate, 20 grams of methylene bromide are added at 40 C.while stirring. The reaction mixture is kept at the same temperature forabout 6 hours. After cooling and filten'ng off from precipitated salts,the reaction mixture is fractionated. There are obtained 35 grams of thedi-(p-hydroxyethyh) mercaptan' boiling at 145 C. at 0.02 mm. Hg.

Example 8 s-cnron -m-i -(octm),

34 grams of di-(fl-hydroxyethyh) mercaptan are dissolved in 125 cc. ofmethyl-ethylketone. 60 grams of potassium carbonate and 2 grams ofcopper powder are added. At 80 C. 77 grams 0,0-diethyl-thibphosphoricacid chloride are added and the temperature of 80 C. is kept for furtherhours. The following procedure is carried out in accordance with Example7. There are obtained 60 grams of the crude ester which cannot bedistilled in high vacuum.

v 6 I claim: 1. A thiophosphoric acid ester of the formula I l/ RCH2-sA-0P in which R stands for a member selected from the groupconsisting of lower alkyland phenyl radicals, A stands for a loweralkylene chain and R stands for a member selected from the groupconsisting of (1) carbo-lower alkoxy, (2) N,N-di-lower alkylamino loweralkyl, (3) hydroxy lower alkyl mercapto radicals and lower alkoxyloweralkyl mercapto radicals, (4) lower alkyl mercapto, phenyl mercapto,lower alkoxy and phenoxy radicals.

2. A process for the preparation of thiophosphoric acid esters of theformula in which R stands for a member selected from the groupconsisting of lower alkyland phenyl radicals, A stands for a loweralkylene chain and R stands for a member selected from the groupconsisting of 1) carbo-lower alkoxy, (2) N,N-di-lower alkylamino loweralkyl, (3) hydroxy lower alkyl mercapto radicals and lower alkoxyloweralkyl mercapto radicals, (4) lower alkyl mercapto, phenyl mercapto,lower alkoxy and phenoxy radicals, which comprises reacting an alcoholof the following forin which R and A have the same significance as abovewith an 0.0-diester of a thiophosphoric acid halide in the presence ofan acid binding agent in an inert solvent.

3. A thiophosphoric acid ester of claim 1 wherein R is a lower alkylradical and R is a carbo-lower alkoxy radical.

4. I A thiophosphoric acid ester of claim 1 wherein each R is a loweralkyl radical and R is a N,N-di-loweralkylamino lower alkyl radical.

5. A thiophosphoric acid ester of claim 1 wherein each R is a loweralkyl radical and R is a lower alkoxy radical.

6. A thiophosphoric acid ester of claim 1 wherein each R is ethyl, A isethylene, and R is methoxy.

7. A thiophosphoric acid ester of claim 1 wherein each R is ethyl, A isethylene, and R is ethoxy.

8. A thiophosphoric acid ester of claim 1 wherein each R is ethyl, A isethylene, and R is isopropoxy.

9. A thiophosphoric acid ester of claim 1 wherein each R is ethyl, A isethylene, and R is secondary-butoxy.

10. A thiophosphoric acid ester of claim 1 wherein each R is ethyl, A isethylene, and R is carbo-ethoxy.

11. A thiophosphoric acid ester of claim 1 wherein each R is ethyl, A isethylene, and R is diethylaminomethyl.

12. A thiophosphoric acid ester of claim 1 wherein each R is ethyl, A isethylene, and R is hydroxy methyl.

References Cited in the file of this patent UNITED STATES PATENTS2,571,989 Schrader Oct. 16,1951

1. A THIOPHOSPHORIC ACID ESTER OF THE FORMULA